A second insider told The Mirror that Hamilton and Scherzinger's busy working schedules put pressure on their relationship, saying: "Increasingly hectic schedules this year have meant limited face-to-face time. They've probably spent more time on the phone or on Skype than they have in person.

"Sadly, Nicole's job on X Factor USA... appears to have come at the cost of her relationship... This, plus Lewis's crazy international jet-set lifestyle, put immeasurable strain on the pair."

The second source added that the separation was "all very amicable" and that Hamilton and Scherzinger remain friends.

Watch a video of Lewis Hamilton and Nicole Scherzinger on the red carpet at this year's National Movie Awards below: